U.S. patent application number 16/379120 was filed with the patent office on 2019-10-10 for radar apparatus and antenna apparatus therefor.
The applicant listed for this patent is MANDO CORPORATION. Invention is credited to Seong Hee Jeong, Jae Eun Lee, Hae Sueng Lim.
Application Number | 20190310359 16/379120 |
Document ID | / |
Family ID | 66102574 |
Filed Date | 2019-10-10 |
United States Patent
Application |
20190310359 |
Kind Code |
A1 |
Lee; Jae Eun ; et
al. |
October 10, 2019 |
RADAR APPARATUS AND ANTENNA APPARATUS THEREFOR
Abstract
The present provides a radar apparatus and an antenna apparatus
for the radar apparatus. The radar apparatus may include two first
transmission antennas disposed on both sides of the transmission
antenna set and the second transmission antenna disposed between
two first transmission antennas spaced apart from the first
transmission antenna by the vertical distance A in a first
direction perpendicular to the ground, and may include the four
receiving antennas disposed apart from each other by a
predetermined horizontal distance, and may transmit the code
divided transmission signals through two transmission antenna
according to the detection mode, so that the vertical information
and the horizontal information of the object can be easily obtained
in the long range detection mode and the short range detection
mode.
Inventors: |
Lee; Jae Eun; (Seoul,
KR) ; Lim; Hae Sueng; (Yongin-si, KR) ; Jeong;
Seong Hee; (Yongin-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MANDO CORPORATION |
Pyeongtaek-si |
|
KR |
|
|
Family ID: |
66102574 |
Appl. No.: |
16/379120 |
Filed: |
April 9, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01S 7/41 20130101; G01S
13/931 20130101; G01S 13/0218 20130101; H01Q 21/065 20130101; G01S
13/42 20130101; G01S 13/86 20130101 |
International
Class: |
G01S 13/02 20060101
G01S013/02; G01S 13/86 20060101 G01S013/86; G01S 13/93 20060101
G01S013/93; G01S 13/42 20060101 G01S013/42; G01S 7/41 20060101
G01S007/41 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2018 |
KR |
10-2018-0040833 |
Claims
1. A radar apparatus, comprising: an antenna member configured to
include a transmission antenna set which includes a first
transmission antenna including a first-1 transmission antenna and a
first-2 transmission antenna arranged at both ends in a horizontal
direction and includes a second transmission antenna arranged
between the first-transmission antenna and the first-2 transmission
antenna and spaced apart from the first transmission antenna by a
predetermined vertical distance in a first direction perpendicular
to a ground, and configured to include a receiving antenna set
which includes at least one receiving antenna disposed at the same
vertical position as the first transmission antenna; a transceiver
configured to select at least one transmission antenna based on a
detection mode among a plurality of detection modes, transmit
transmission signal by using the selected transmission antenna, and
receive reflection signal by using all of the receiving antennas;
and a processes configured to process the reflection signal
received from the receiving antenna and to acquire at least one of
a horizontal information or a vertical information of an
object.
2. The radar apparatus of claim 1, wherein the receiving antenna
set is configured to include a first receiving antenna, a second
receiving antenna, a third receiving antenna and a fourth receiving
antenna which are sequentially spaced apart from each other in a
second direction perpendicular to the first direction, and, wherein
each of the first receiving antenna and fourth receiving antennas
is spaced apart from a midpoint between the second receiving
antenna and the third receiving antenna by a first horizontal
distance.
3. The radar apparatus of claim 2, wherein each of the first-1
transmission antenna, the first-2 transmission antenna and the
second transmission antenna includes 4 or 6 array antennas.
4. The radar apparatus of claim 3, wherein the first-1 transmission
antenna and the first-2 transmission antenna are arranged apart
from each other by a second horizontal distance corresponding twice
of the first horizontal distance in the second direction.
5. The radar apparatus of claim 4, wherein each of the first
receiving antenna and the fourth receiving antennas includes two
array antennas, and each of the second receiving antenna and the
third receiving antenna includes one array antenna, and, wherein
the process operable to synthesize signals received from the second
receiving antenna and the third receiving antenna and process the
synthesized signal as one channel signal.
6. The radar apparatus of claim. 3, wherein the plurality of
detection modes includes a first detection mode for acquiring the
horizontal information of the object in medium or long distance,
and the transceiver is operable to transmit code-divided
transmission signals from the first-1 transmission antenna and the
first-2 transmission antenna and is operable to receive the
reflection signal at all of the receiving antennas in the first
detection mode.
7. The radar apparatus of claim 6, wherein the plurality of
detection modes include a second detection mode for acquiring the
vertical information of the object, and the transceiver is operable
to transmit code-divided transmission signals by using the second
transmission antenna and one of the first-1 transmission antenna
and the first-2 transmission antenna, and is operable to receive
reflection signals at all of the receiving antennas is the second
detection mode.
8. The radar apparatus of claim 7, wherein the plurality of
detection modes include a third detection mode for acquiring at
least one of the horizontal information or the vertical information
of the object in short distance, and the transceiver is operable to
transmit the transmission signal by using one transmission antenna
selected among the first-1 transmission antenna, the second
transmission antenna and the first-2 transmission antenna, and is
operable to receive reflection signals at all of the receiving
antennas in the third detection mode.
9. The radar apparatus of claim 7, wherein the radar apparatus is
operable to detect the vertical information of the object in the
medium or long distance and the horizontal and the vertical
information of the object in the short distance in the second
detection mode.
10. The radar apparatus of claim 8, wherein the radar apparatus is
operable to utilize the transmission signal with a frequency band
and a waveform of different from each other in at least two
detection modes among the first to third detection modes.
11. An antenna apparatus for a radar apparatus, the antenna
apparatus comprising: a transmission antenna set which includes a
first transmission antenna including a first-1 transmission antenna
and a first-2 transmission antenna arranged at both ends in a
horizontal direction and includes a second transmission antenna
arranged between the first-transmission antenna and the first-2
transmission antenna and spaced apart from the first transmission
antenna by a predetermined vertical distance in a first direction
perpendicular to the ground; and a receiving antenna set which
includes at least one receiving antenna disposed at the same
vertical position as the first transmission antenna.
12. The antenna apparatus of claim 11, wherein the receiving
antenna set is configured to include a first receiving antenna, a
second receiving antenna, a third receiving antenna and a fourth
receiving antenna which are sequentially spaced apart from each
other in a second direction perpendicular to the first direction,
and wherein each of the first receiving antenna and fourth
receiving antennas spaced apart from a midpoint between the second
receiving antenna and the third receiving antenna by a first
horizontal distance.
13. The antenna apparatus of claim 12, wherein each of the first-1
transmission antenna, the first-2 transmission antenna and the
second transmission antenna includes 4 or 6 array antennas.
14. The antenna apparatus of claim 13, wherein the first-1
transmission antenna and the first-2 transmission antenna are
arranged apart from each other by a second horizontal distance
corresponding twice of the first horizontal distance in the second
direction.
15. The antenna apparatus of claim 14, wherein each of the first
receiving antenna and the fourth receiving antennas includes two
array antennas, and each of the second receiving antenna and the
third receiving antenna includes one array antenna, and wherein the
second receiving antenna and the third receiving antenna are
operable to be combined and used as one receiving channel.
16. The antenna apparatus of claim 15, wherein, in a first
detection mode for acquiring the horizontal information of the
object in medium or long distance, the first-1 transmission antenna
and the first-2 transmission antenna are operable to transmit
code-divided transmission signals, and all of the receiving
antennas are operable to receive the reflection signal.
17. The antenna apparatus of claim 16, wherein, in a second
detection mode for acquiring the vertical information of the
object, the second transmission antenna and one of the first-1
transmission antenna and the first-2 transmission antenna are
operable to transmit code-divided transmission signals, and all of
the receiving antennas are operable to receive the reflection
signal.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Korean Patent
Application No. 10-2018-0040833, filed on Apr. 9, 2018, which is
hereby incorporated by reference for all purposes as if fully set
forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present disclosure relates to a radar apparatus and an
antenna apparatus, more particularly, to a radar apparatus
including a multi-input multi-output (hereafter, referred to as
`MIMO`) antenna and obtaining azimuth information and elevation
information of an object at a mid/long distance and a short
distance by using the antenna.
2. Description of the Prior Art
[0003] A radar apparatus for vehicles should have high resolution
and angular resolving power. For example, automotive radars for
preventing a front collision can determine interruption by
extracting an angle in in-path cut-in and cut-out of a vehicle
running ahead in adjacent lanes. That is, is possible to secure
safety for a driver by reducing mis-detecting of a target and
estimating a collision situation in cut-in and cut-out using the
high resolution and angular resolving power.
[0004] Further, automotive radars require a mid/long-range
detection function for sensing objects at long distances in a
relatively small angular range and a short-range detection function
for sensing objects at short distances within a relatively large
angle range, using one antenna system.
[0005] Further, a radar apparatuses generally include arrangement
of a plurality of receiving antennas to obtain high angular
resolving power. That is, radar apparatuses of the related art use
a structure that increases angular resolving power by arranging
receiving antennas in a plurality of channels.
[0006] Radar apparatuses having a structure including arrangement
of a plurality of receiving antennas in the related art are
structurally large in size due to the antennas and require many
elements related to transceiver (that is, an RF circuit), so the
size of the entire antenna system is increased.
[0007] However, at present, the portion of vehicles where a radar
apparatus can be mounted is limited due to a plurality of the
support structures such as an ultrasonic sensor in the bumper, the
license plate and the fog lamps, so radar apparatuses are
unavoidably limited in size.
[0008] Recently, a MIMO radar has been developed to reduce the size
of automotive radars.
[0009] The MIMO radar has an effect of expanding an aperture of a
receiving antenna by arranging transmission antennas with an
appropriate gap, so it has been recently actively researched in
order to reduce the number of RF chips and without reducing
performance.
[0010] The MIMO radars for a vehicle generally provide an efficient
aperture expansion effect by usually arranging two transmitting
channels and a several receiving channels, and this structure has
been proposed for long-range radars or mid-range radars of
automotive radars.
[0011] However, automotive radars need to detect wide areas not
only at a mid/long distance, but a short distance, so they require
an additional sensor for short-range sensing, and accordingly, the
costs and complication are increased.
[0012] Accordingly, it is required to combine a mad/long-range
radar and a short-range radar for automotive radars, and generally,
different transmission antennas are configured and receiving
antennas are shared to combine a mid/long-range radar and a
short-range radar. However, performances such as resolving power of
the mid/long-range radar are deteriorated and performances such as
detecting range of the short-range radar are deteriorated, so their
performances cannot be maximized.
[0013] Accordingly, there is a need to develop a radar apparatus
that can detect both of a mid/long distance and a short distance
and can be down-sized with resolution and angular resolving power
maintained at a high level, but conventional radar apparatuses
cannot satisfy these requirements.
SUMMARY OF THE INVENTION
[0014] For this background, an object of the present disclosure is
to provide a radar apparatus of which the performance can be
maximized up to not only mid/long-range performance, but
short-range performance by efficiently arranging a plurality of
transmission antennas and a plurality of receiving antennas.
Another object of the present disclosure is to provide an antenna
that can perform multi-input multi-output (MIMO) by a plurality of
transmission antennas and a plurality of receiving antennas, and a
radar apparatus including the antenna.
[0015] Another object of the present disclosure is to provide an
antenna system and a radar apparatus with the antenna system which
includes a first transmission antenna set including a first-1
transmission antenna and a first-2 transmission antenna arranged at
both ends in a horizontal direction, and includes a second
transmission antenna arranged between the first-1 transmission
antenna and the first-2 transmission antenna and spaced apart from
the first transmission antenna by a predetermined vertical distance
B in a first direction perpendicular to the ground. In addition,
code-divided transmission signals may be transmitted from the
selected two transmission antennas at the same time, a reflection
signal reflected by the object may received and processed, so that
can acquire the horizontal information and vertical information of
a target object both in the mid/long range detection mode and the
short range detection mode.
[0016] Another object of the present disclosure is to provide an
antenna structure of a radar device for obtaining horizontal
information and vertical information for a target object in which
two of the first transmission antennas disposed on both sides and
the second transmission antenna disposed between two of the first
transmission antennas among three transmission antennas are
arranged apart from each other by a predetermined vertical distance
in a first direction perpendicular to the ground, and four
receiving antennas which are arranged apart from each other by a
predetermined horizontal distance in a horizontal direction.
[0017] Another object of the present disclosure is to provide a
radar apparatus in which the shapes of the signal waveform and the
frequency band of the transmission signal in the mid/long range
detection mode and the short range detection mode are different
from each other so that it is possible to improve the measurement
resolution of the horizontal/vertical information of the object in
both the long distance and the near distance while avoiding
interference with other radar devices.
[0018] In accordance with an aspect of the present disclosure,
there is provided a radar apparatus, the radar apparatus including:
an antenna member configured to include a transmission antenna set
which includes a first transmission antenna including a first-1
transmission antenna and a first-2 transmission antenna arranged at
both ends in a horizontal direction and includes a second
transmission antenna arranged between the first-1 transmission
antenna and the first-2 transmission antenna and spaced apart from
the first transmission antenna by a predetermined vertical distance
in a first direction perpendicular to a ground, and configured to
include a receiving antenna set which includes at least one
receiving antenna disposed at the same vertical position as the
first transmission antenna; a transceiver configured to select at
least one transmission antenna based on a detection mode among two
or more detection modes, transmit transmission signal by using the
selected transmission antenna, and receive reflection signal by
using all of the receiving antennas; and a processor configured to
process the reflection signal received from the receiving antenna
and to acquire at least one of a horizontal information or a
vertical information of an object.
[0019] Furthermore, the receiving antenna set may include a first
receiving antenna, a second receiving antenna, a third receiving
antenna, a fourth receiving antenna which are sequentially spaced
apart from each other in a second direction perpendicular to the
first direction. In addition, the first receiving antenna and
fourth receiving antennas are spaced apart from a midpoint between
the second receiving antenna and the third receiving antenna by a
first horizontal distance respectively.
[0020] Each of the first-1 transmission antenna, the first-2
transmission antenna and the second transmission antenna may
include 4 or 6 array antennas. In addition, the first-1
transmission antenna and the first-2 transmission antenna are
arranged at both ends in a horizontal direction spaced apart from
each other by a second horizontal distance corresponding twice of
the first horizontal distance A.
[0021] In addition, the second transmission antenna may include 4
or 6 transmission antennas, and may be disposed between the first-1
transmission antenna and the first-2 transmission antenna.
[0022] In this case, the first receiving antenna RX0 and the fourth
receiving antennas may include two array antennas, and the second
receiving antenna and the third receiving antenna may include one
array antenna. The signals received from the second receiving
antenna and the third receiving antenna may be combined and
processed as one channel signal by the processor.
[0023] In order to obtain the horizontal information of the object,
in the first detection mode for a medium/long range detection, the
transceiver may transmit a code-divided transmission signal from
the first-1 transmission antenna and the first-2 transmission
antenna arranged at both ends and may receive reflection signals at
all of the receiving antennas.
[0024] In the second detection mode for obtaining the vertical
information of the object, the transceiver may transmit
code-divided transmission signals from the second transmission
antenna and one of the first-1 transmission antenna and the first-2
transmission antenna, and may receive reflection signals at all of
the receiving antennas.
[0025] In the third detection mode for obtaining the horizontal
information or the vertical information of the object existing in
the short distance, the transceiver may transmit the transmission
signal by using one transmission antenna selected among the first-1
transmission antenna, the second transmission antenna and the
first-2 transmission antenna, and may receive reflection signals at
all of the receiving antennas.
[0026] In accordance with another aspect of the present disclosure,
there is provided an antenna apparatus, the antenna apparatus
including: a transmission antenna set which includes a first
transmission antenna including a first-1 transmission antenna and a
first-2 transmission antenna arranged at both ends in a horizontal
direction and includes a second transmission antenna arranged
between the first-1 transmission antenna and the first-2
transmission antenna and spaced apart from the first transmission
antenna by a predetermined vertical distance in a first direction
perpendicular to a ground; and
[0027] a receiving antenna set which includes at least one
receiving antenna disposed at the same vertical position as the
first transmission antenna.
[0028] As described below, according to the present disclosure, it
is possible to provide a radar device capable of maximizing a short
distance detection performance as well as a medium/long range
detection performance through an efficient arrangement of a
plurality of transmission antennas and the plurality of receiving
antennas.
[0029] More specifically, the radar apparatus may include the
antenna structure in which two of first transmission antennas are
disposed at both ends and the second transmission antenna is
arranged between the first-1 transmission antenna and the first-2
transmission antenna and spaced apart from the first transmission
antenna by a predetermined vertical distance, and may transmit
code-divided transmission signals through two transmission antenna
selected according to the detection mode and process the reflection
signal received at the receiving antenna, so that the radar
apparatus can acquire the horizontal information and the vertical
information with high resolution both in the medium/long range
detection mode and the short range detection mode. According the
antenna apparatus of the present disclosure, two transmission
antennas arranged on both sides among the three transmission
antennas may be disposed apart from the second transmission antenna
disposed between two transmission antennas by a predetermined
vertical distance in a first direction perpendicular to the ground,
and the four receiving antennas may be disposed apart from each
other by a predetermined horizontal distance, so that the vertical
information and the horizontal information of the object can be
easily obtained in the long range detection mode and the short
range detection mode.
[0030] According the antenna apparatus and the radar apparatus of
the present disclosure, the shapes of the frequency band and the
signal waveform of the transmission signal may be different from
each other in the long range detection mode and the short range
detection mode, so that the measurement resolution of the
horizontal/vertical information of the object may be improved in
both long range detection mode and the short range detection mode,
and an interference with other radar devices may be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 shows an example of a radar apparatus having a common
multi-antenna;
[0032] FIG. 2 is a schematic diagram of a radar apparatus according
to an embodiment of the present disclosure;
[0033] FIG. 3 shows a first embodiment of arrangement of a
plurality of transmission antennas and a plurality of receiving
antennas included in an antenna system included in the radar
apparatus according to an embodiment of the present disclosure;
[0034] FIG. 4 shows a case of detecting azimuth information using
the radar apparatus according to the present disclosure,
particularly, in which a timing diagram of signals in a
mid/long-range detection mode (FIG. 4A) and an equivalent state
diagram of transmitting and receiving antennas in this case (FIG.
4B) are provided;
[0035] FIG. 5 shows a case of detecting elevation information or
vertical information using the radar apparatus according to the
present disclosure, in which a timing diagram of signals in a
second detection mode for detecting vertical information (FIG. 5A)
and an equivalent state diagram of transmitting and receiving
antennas in this case (FIG. 5B) are provided;
[0036] FIG. 6 is a flowchart illustrating a signal processing
method provided by the radar apparatus according to an embodiment
of the present disclosure; and,
[0037] FIG. 7 shows differences in a signal waveform and a
frequency band in a mid/long-range detection mode and a
short-detection mode in a radar apparatus according to an
embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0038] Hereinafter, embodiments the present disclosure be described
with reference to exemplary diagrams. In the specification, in
adding reference numerals to components throughout the drawings, it
should be noted that like reference numerals designate like
components even though components are shown in different drawings.
Further, in describing embodiments of the present disclosure,
well-knows functions or constructions will not be described in
detail since they may unnecessarily obscure the understanding of
the present disclosure.
[0039] Further, terms such as `first`, `second`, `B`, `(a)`, and
`(b)` may be used for describing components of the present
disclosure. These terms are used only for discriminating the
components from other components, so the essence or order of the
components indicated by those terms is not limited. It should be
understood that when one element is referred to as being "connected
to", "combined with" or "coupled to" another element, it may be
connected directly to or coupled directly to another element, or
another element may be "connected", "combined", or "coupled"
between them.
[0040] FIG. 1 shows an example of a radar apparatus having a
general multi-antenna.
[0041] As shown in FIG. 1a, a radar apparatus has an antenna system
in which two transmission antennas TX0 and TX1 are disposed in the
same direction at the upper portion and four receiving antennas
RX0.about.RX3 are disposed in the same direction at the lower
portion.
[0042] When a signal is to be transmitted, one transmission antenna
is selected by a first switch SW1 and transmits a transmission
signal.
[0043] A reception signal reflected from an object is received by
one receiving antenna switched by a second switch SW2.
[0044] A signal processor DSP can measure the distance from the
object and the relative speed of the object by measuring a phase
change, a magnitude change, a frequency difference etc by
amplifying a received reflection signal and comparing the amplified
signal with the transmission signal.
[0045] In FIG. 1a, the antennas are one-line array antennas.
[0046] FIG. 1b shows an example of another multi-antennal radar
apparatus, in which one transmission antenna TX0, a plurality of
receiving antennas RX0.about.RX2, and one transmitting-receiving
antenna RX3/TX1 are arranged with gaps therebetween and the
antennas are elongated in the same directions.
[0047] In this configuration, when a signal is to be transmitted,
one of the transmission antenna TX0 and the transmitting-receiving
antenna RX3/TX1 is selected by a first switch SW1 and transmits a
transmission signal.
[0048] A reception signal reflected from an object is received by
one of the receiving antennas RX0.about.RX2 and the
transmitting-receiving antenna RX3/TX1 selected by a second switch
SW2.
[0049] A signal processor DSP can measure the distance from the
object and the relative speed of the object by measuring a phase
change, a magnitude change, a frequency difference etc. by
amplifying a received reflection signal and comparing the amplified
signal with the transmission signal.
[0050] Although the radar apparatus having the antenna system shown
in FIG. 1 can perform mid/long-range sensing and short-range
sensing, has difficulty in having sufficient resolution or angular
resolving power in both of the mid/long-range sensing and
short-range sensing.
[0051] Further, in the antenna system shown in FIG. 1a, a plurality
of transmission antennas is elongated in the same direction and a
plurality of receiving antennas is also elongated in the same
direction, and in FIG. 1b, all transmitting and receiving antennas
are elongated in the same direction.
[0052] Therefore, according to the antenna system, it is possible
to exactly sense azimuth information, but it is difficult to
precisely measure elevation information.
[0053] That is, in the antenna system shown in FIG. 1, any one or
more of the receiving antennas RX0 to RX3 receive a reflection
signal, but the receiving antennas have different horizontal
arrangement characteristic from the transmission antenna TX0 or
TX1, so there are differences in the reception signals received by
the receiving antennas. Accordingly, azimuth information can be
exactly measured by analyzing the differences.
[0054] However, the receiving antennas have the same arrangement
characteristic in the elevation direction as the transmission
antenna TX0 or TX1, so there is no difference in the reception
signals received by the receiving antennas, and thus, it is
difficult to measure elevation information of an object.
[0055] Accordingly, in an embodiment of the present disclosure,
there is provided an antenna system in which one of the plurality
of transmission antennas is spaced apart from the other
transmission antennas by a predetermined vertical distance in the
vertical direction (first direction perpendicular to the ground),
and transmission signals are simultaneously transmitted from two
transmission antennas spaced apart in the vertical direction, and
the reflection signal received from the plurality of receiving
antennas is processed, so that it is possible to obtain the
horizontal information and the vertical information of the object
with good resolution both in the long range detection mode and the
short range detection mode.
[0056] FIG. 2 is a block diagram of a radar apparatus 100 according
to an embodiment of the present disclosure.
[0057] As shown in FIG. 2, the radar apparatus 100 according to an
embodiment of the present disclosure includes an antenna system 110
or an antenna member including a plurality of transmission antennas
and a plurality of receiving antennas, a transceiver 120
transmitting transmission signals and receiving reception signals
through the antenna system 110, and a processor 130 for processing
the reception signal and calculating horizontal and/or vertical
position information of the object. The radar apparatus is also
called a radar sensor.
[0058] For convenience, the up-direction of the vertical directions
is defined as a first direction and the down-direction of the
vertical directions is defined as a second direction herein.
[0059] The antenna system 110 may include a transmission antenna
set including two of first transmission antennas disposed at both
ends of the transmission antenna set in a horizontal direction and
a second transmission antenna disposed between two of first
transmission antennas spaced apart from the first transmission
antenna by a vertical distance B in a first direction perpendicular
to a ground, and may include a receiving antenna set including at
least one receiving antenna disposed at the same vertical position
as the first transmission antenna.
[0060] As an example of the antenna system 110, the transmission
antenna set may include three transmission antennas extending in a
first direction perpendicular to the ground or in a vertical
direction, and the receiving antenna set may include four receiving
antennas extending in the first direction and disposed apart from
the transmission antenna set by predetermined distance in a second
direction perpendicular to the first direction.
[0061] That is, the radar apparatus according to the present
embodiment has three transmission channels (transmission antennas)
and four receiving channels (receiving antennas).
[0062] In addition, the transmission antenna set may include a
first transmission antenna including a first-1 transmission antenna
TX0 and a first-2 transmission antenna TX2 which have the same
vertical position as the receiving antennas and disposed apart from
each other by the second horizontal distance 2A in the horizontal
direction to constitute both ends of the transmission antenna set,
and may include a second transmission antenna TX1 arranged between
the first-1 transmission antenna TX0 and the first-2 transmission
antenna TX2 spaced apart from the first transmission antenna by a
predetermined vertical distance B in a first direction (the
vertical direction).
[0063] The specific configuration of the antenna unit 110 will be
described in more detail with reference to FIG. 3 below.
[0064] The transceiver 120 includes: a transmitter that switches to
one of the transmission antennas included in the antenna system 110
having a structure to be described with reference to FIG. 2 etc and
transmits a transmission signal through the switched transmission
antenna through a multi-transmitting channel assigned to the
transmission antennas; and a receiver that switches to one of the
receiving antennas and receives a reception signal that is a
reflection signal of the transmission signal reflected from a
target through the switched receiving antenna or through a
multi-receiving channel assigned to the receiving antennas.
[0065] More specifically, the transceiver 120 according to the
present embodiment may be controlled to transmit code-divided
transmission signals from the first-1 transmission antenna TX0 and
the first-2 transmission antenna TX2 in the first detection mode
for acquiring the horizontal information of a medium/long distance
object, and may be controlled to receive reflection signals at all
of the receiving antennas in order to acquire the horizontal
information such as the azimuth information of the object in a
medium/long distance.
[0066] In addition, in the second detection mode, the transceiver
may be controlled to transmit code-divided transmission signals
through one first transmission antenna among two first transmission
antennas and the second transmission antenna spaced apart from the
first transmission antenna, and may be controlled to receive
reflection signals at all of the receiving antennas is order to
acquire the vertical information such as the elevation information
of the object both in a medium/long distance and short
distance.
[0067] In addition, the processor 130 may obtain the horizontal
information such as an azimuth angle of a target object in a short
distance by using the received signals received from all of the
receiving antennas and one of the code-divided transmission signals
in both of two detection modes.
[0068] At this instance, the processor 130 may synthesize the
signals received from the second receiving antenna RX1 and the
third receiving antenna RX2 and may process it as one channel
signal.
[0069] The transmitter included in the transceiver 120 includes an
oscillator that generates a transmission signal for one
transmitting channel assigned to a switched transmission antenna or
a multi-channel assigned to a plurality of transmission antennas.
The oscillator, for example, may include a voltage-controlled
oscillator (VCO) and an oscillator.
[0070] The receiver included in the transceiver 120 includes: a
low-noise amplifier (LNA) that low-noise amplifies the reception
signal received through one receiving channel assigned to a
switched receiving antenna or through a multi-receiving channel
assigned to a plurality of transmission antenna; a mixer that mixes
the low-noise amplified reception signal; an amplifier that
amplifies the mixed receiving signals; and an analog-to-digital
converter (ADC) that generates reception data by digital-converting
the amplified reception signal.
[0071] Referring to FIG. 2, the radar apparatus 100 according to an
embodiment of the present disclosure includes a processor 130 that
controls a transmission signal and performs signal processing using
reception data. The processor 130 allows for reducing costs and
hardware size too by efficiently distributing signal processing,
which requires a large amount of calculation, to a first processor
and a second processor.
[0072] The first processor included in the processor 130 is a
pre-processor for the second processor and can obtain transmission
data and reception data, control generation of a transmission
signal by the oscillator based on the obtained transmission data,
synchronize the transmission data and reception data, and changes
frequencies of the transmission data and reception data.
[0073] The second processor a post-processor that actually performs
processing using the processing result of the first processor and
can perform CFAR (Constant False Alarm Rate) calculation, tracking,
and target selection on the basis of the reception data with
frequency changed by the first processor, and perform extract
angular information, speed information, and distance information on
a target.
[0074] The first processor can buffer the obtained transmission
data and reception data into a sample size that can be processed
for one cycle and change the frequency. The frequency change by the
first processor may use Fourier transform such as FFT (Fast Fourier
Transform).
[0075] The second processor may perform second Fourier transform on
the signals that has undergone first Fourier transform (FFT) by the
first processor and the second Fourier transform, for example, may
be Discrete Fourier Transform (hereafter, referred to as `DET`).
Further, it may be chirp-DFT of DFT.
[0076] The second processor obtains frequency values corresponding
to a second Fourier transform length (K) through the second Fourier
transform, calculates a bit frequency having the largest power for
each chirp period on the basis of the obtained frequency values,
and obtain speed information and distance information of an object
on the basis of the calculated bit frequency, whereby it can detect
an object.
[0077] Meanwhile, the radar apparatus according to this embodiment
may include the antenna systems shown in FIGS. 3, and the
transceiver 120 and the processor 130 may perform a predetermined
signal transmitting/receiving manner and information calculation
manner in order to acquire the vertical information and horizontal
information of the object in both the mid/long range detection mode
and the short range detection mode. These manners will be described
in more detail below with reference to FIGS. 4-6.
[0078] The antenna system 110 included in the radar apparatus 100
according to an embodiment of the present disclosure may include a
plurality of transmission antennas and a plurality of receiving
antennas, and each of the transmission antennas and the receiving
antennas may be array antennas of which a plurality of
transmitting/receiving elements is connected in series by
transmission wires, but they are not limited thereto.
[0079] However, the antennas used in this embodiment are elongated
in predetermined directions and the directions mean the directions
in which the antennas are elongated with respect to a transmission
port connected to a processor 130.
[0080] FIG. 3 shows a first embodiment of arrangement of a
plurality of transmission antennas and a plurality of receiving
antennas included in an antenna system included in the radar
apparatus according to an embodiment of the present disclosure.
[0081] For convenience, the up-direction of the vertical directions
is defined as a first direction and the down-direction of the
vertical directions is defined as a second direction herein.
[0082] In the antenna system according to as example of FIG. 3, the
receiving antenna set may include a total of four receiving
antennas, and the first receiving antenna RX0, the second receiving
antenna RX1, the third receiving antenna RX2, and the fourth
receiving antenna RX3 are sequentially arranged spaced apart in the
second direction perpendicular to the first direction.
[0083] In addition, each of the first receiving antennas RX0 and
the fourth receiving antennas RX3 may be disposed apart from a
midpoint between the second receiving antenna RX1 and the third
receiving antenna RX2 by a first horizontal distance A.
[0084] Each of the first receiving antenna RX0 and the fourth
receiving antenna RX3 may be configured as two array antennas and
the second receiving antenna RX1 and each of the third receiving
antenna RX2 may be configured as a single array antenna. The
processor may synthesize the signals received from the second
receiving antenna RX1 and the third receiving antenna RX2 to
process as one channel signal.
[0085] Alternatively, each receiving antenna may comprise a larger
number of array antennas than one or two array antennas.
[0086] The transmission antenna set may include a total of three
transmission antennas including the first transmission antenna and
the second transmission antenna.
[0087] The first transmission antenna may include the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
which are disposed in both ends in the horizontal direction and
each of which includes 4 or 6 array antennas.
[0088] The second transmission antenna may include the second
transmission antenna TX1 which is disposed between the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
in the horizontal direction, and is spaced apart from the first
transmission antenna by the vertical distance B in the vertical
direction.
[0089] Meanwhile, the first-1 transmission antenna TX0 and the
first-2 transmission antenna TX2 constituting the first
transmission antenna may be disposed apart from each other by the
second horizontal distance 2A corresponding to twice of the first
horizontal distance A in the second direction (vertical
direction).
[0090] In addition, the second transmission antenna TX1 is disposed
in the middle between the first-1 transmission antenna TX0 and the
first-2 transmission antenna TX2 constituting the first
transmission antenna so that consequently the second transmission
antenna TX1 may be spaced apart from each of the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
by a first horizontal distance A.
[0091] The second transmission antenna TX1 may be also constituted
by 4 or 6 array antennas extending to the first direction, but may
not limited thereto.
[0092] That is, each of the first-1 transmission antennas TX0, the
first-2 transmission antenna TX2 and second transmission antennas
TX1 may be configured to include 4 or 6 array antennas which are
connected to the same feed line to and simultaneously transmit a
transmission signal. Alternatively, each of the transmission
antenna may be configured to include one or more array antennas
depending on the required detection resolution instead of 4 or 6
array antenna configurations.
[0093] In general, as the aperture of the transmission antenna
becomes larger, the transmission beam becomes sharp and the
linearity of the transmission beam becomes higher. Therefore, it is
possible to further improve the straightness of the transmission
signal and the detecting distance by setting the number of array
antennas of each of the first-1 transmission antenna TX0 and the
first-2 transmission antenna TX2 used for acquiring horizontal
information of the object in the long range detection mode to four
or six.
[0094] The each of the array antennas constituting the transmission
antenna and the receiving antenna may include a plurality of
elements or patches connected through a transmission line and a
plurality of elements or patches may be extended to up-direction of
the first direction from a start point that is a feeding port 320
connected to a chip 310 including a signal processor.
[0095] Meanwhile, the transmission antennas and the receiving
antennas constituting the antenna apparatus according to the
present embodiment may have a predetermined arrangement interval
and will be described in detail below.
[0096] First, the center point P between the second receiving
antenna RX1 and the third receiving antenna RX2 is located apart
from the center point of the two array antennas constituting the
first receiving antenna RX0 by the first horizontal distance A in
the horizontal direction (i.e. the second direction). In addition,
the center point of the two array antennas constituting the fourth
receiving antenna RX3 is spaced apart from the center point P
between the second receiving antenna RX1 and the third receiving
antenna RX2 by a first horizontal distance A.
[0097] That is, each of the first receiving antenna RX0 and a
fourth receiving antenna RX4 may be disposed at positions spaced
apart from the midpoint. P between the second receiving antenna RX1
and the third receiving antenna RX2 by a first horizontal distance
A.
[0098] Meanwhile, the second receiving antenna RX1 and the third
receiving antenna RX2 may be arranged to be spaced apart from each
other by a half (0.5.lamda.) of the wavelength of the transmission
signal in the horizontal direction. In addition, an interval
between the two array antennas constituting each of the first
receiving antenna RX0 and the fourth receiving antenna RX3 may also
be a half (0.5.lamda.) of the wavelength of the transmission
signal.
[0099] In addition, the interval between each of the four or six
array antennas constituting each of the three transmission antennas
may also be arranged to be spaced by a half (0.5.lamda.) of the
wavelength of the transmission signal.
[0100] Furthermore, the second receiving antenna RX1 and the third
receiving antenna RX2 may be combined or synthesized and used as
one receiving channel. That is, the processor 130 according to the
present embodiment may synthesize the signals received from the
second receiving antenna RX1 and the third receiving antenna RX2
and process the synthesized signal as a single receiving
signal.
[0101] In this manner, the signals received from the second
receiving antenna RX1 and the third receiving antenna RX2 are
synthesized to be used as one channel signal, and the horizontal
distance between the second receiving antenna RX1 and the third
receiving antenna RX2 is set to a half (0.5.lamda.) of the
wavelength of the transmission signal, so that the angle ambiguity
due to the grating lobe may be eliminated.
[0102] That is, the grating lobe may occur because the interval
between the receiving antennas is equal to or greater than a half
(0.5.lamda.) of the wavelength of the transmission signal. However,
according to the present embodiment, the second receiving antenna
RX1 and the third receiving antenna RX2 may be disposed so as the
horizontal distance between the second receiving antenna RX1 and
the third receiving antenna RX2 is 0.5.lamda. and the angular
information extracted from the two channels is compared and
compensated, so that the angle uncertainty due to the grating lobe
may be minimized.
[0103] As described above, the vertical information of the object
such as an elevation angle may be accurately measured by arranging
at least two of the transmission antennas among the plurality of
the transmission antennas constituting the transmission antenna
being apart from each other by a predetermined vertical distance B
in the vertical direction perpendicular to the ground.
[0104] In this case, the vertical distance B may be determined in
consideration of the frequency of the transmission signal and the
measurement accuracy of vertical information of the object.
[0105] In the antenna system of the radar apparatus according to
the present embodiment, is the first detection mode for acquiring
the horizontal information of the object in the long distance, the
horizontal distance 22 between two transmission antennas, that is,
the first-1 transmission antenna TX0 and the first-2 transmission
antenna TX2 for simultaneously transmitting a transmission signal
by code division may be same distance as the horizontal distance 2A
between the two receiving antennas disposed at the outermost of the
four receiving antennas constituting the receiving antenna set,
that is, the first receiving antenna RX0 and the fourth receiving
antenna RX3.
[0106] According to this arrangement, as described below, the
entire aperture of the entire receiving antenna including the
virtual receiving antenna formed in the receiving antenna set by
the code division transmission and the real receiving antenna as
the actual receiving antenna may be expanded, thereby the
measurement resolution of the horizontal information in the
mid/long long range detection mode may be improved.
[0107] The formation of the virtual receiving antenna and the
corresponding aperture expansion effect will be described in more
detail below with reference to FIG. 4.
[0108] In addition, the horizontal distance 2A between the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
for simultaneously transmitting a transmission signal by code
division is set to a same distance as the horizontal distance 2A
between the first receiving antenna RX0 and the fourth receiving
antenna RX3, so that the transmission beam may be kept sharp and
thereby the detection performance of the radar may be improved.
[0109] In addition, it is possible to form a grating lobe occurring
a deterioration of the performance of the antenna at the position
away from the main beam or the main lobe thereby the horizontal
direction detection resolution in both detection modes may be
improved.
[0110] FIG. 4 shows a case of detecting azimuth information using
the radar apparatus according to the present disclosure,
particularly, in which a timing diagram of signals in a
mid/long-range detection mode (FIG. 4A) and an equivalent state
diagram of transmitting and receiving antennas in this case (FIG.
4B) are provided.
[0111] In this disclosure, the detection mode for obtaining the
horizontal information of the long distance object may be referred
to as a first detection mode, the detection mode for obtaining
vertical information of the object is referred to as a second
detection mode, and the detection mode for obtaining the position
information of the short distance object may be referred to as a
third detection mode.
[0112] The code division transmission signals may be simultaneously
transmitted by the first-1 transmission antenna TX0 and the first-2
transmission antenna TX2 in the transmission mode in order to
detect the horizontal information of the object at the medium or
long distance by using the radar according to the present
invention.
[0113] Meanwhile, in the reception mode in which the signal
reflected from the object is received, the signals received from
all the receiving antennas included in the receiving antenna set,
i.e., the receiving antennas RX0 through RX3 may be used to
acquiring the horizontal information of the object at the medium or
long distance. At this case, the signals received from the second
receiving antenna RX1 and the third receiving antenna RX2 may be
synthesized and used as one channel signal.
[0114] In the following description, each of a total of three
transmission antennas TX0, TX1, and TX2 included in the
transmission antenna set may be represented by the respective
transmission channel, and each of total of four receiving antennas
RX1, RX2, RX3 and RX4 may be expressed as the respective receiving
channel.
[0115] Accordingly, the radar apparatus according to the present
embodiment may utilize two transmission channels and three
receiving channels for acquiring the horizontal information of the
object in the long range detection mode. Specifically, the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
of the two transmission channels may simultaneously transmitting
the code-divided transmission signals in the transmission mode, and
the receiving signal received from the three receiving channels
(i.e., three channels of RX0, RX1+RX2 and RX3) may be used in the
receiving mode.
[0116] FIG. 4A is a timing diagram of the signal transmission and
reception in the mid/long range detection mode.
[0117] Referring to FIG. 4A, the first-1 transmission antenna TX0
and the first-2 transmission antenna TX2 may be turned ON for a
predetermined period of time in one predetermined detection period
(0.about.T) and may transmit one transmission signal having the
first code A and the other transmission signal having the second
code B at the same time respectively.
[0118] Meanwhile, each of the four receiving antennas RX0 to RX3
may receive the reflection signal during the same detection period
(0.about.T). The processor 10 may analyze the receiving signals
received from four receiving antennas and three channels (RX1 and
RX2 are combined and used as one channel) and may acquire the
horizontal information (width, etc.) of the object in the middle or
long distance.
[0119] FIG. 4B is an equivalent state diagram of transmission and
receiving antennas in the mid/long range detection mode.
[0120] The equivalent state diagram of FIG. 4B may illustrate the
arrangement state of the receiving antennas when two transmission
antennas transmitting the code-divided transmission signals are set
to one transmission channel, and thereby the degree of aperture of
the radar device may be confirmed.
[0121] In case that the signal transmission are performed according
to FIG. 4A in the first detection mode, the position of the first-1
transmission antenna TX0 may be assumed as a reference position in
FIG. 4B since the horizontal information of the object may be not
affected by the vertical separation of the first transmission
antenna and the second transmission antenna.
[0122] In this case, since the first-1 transmission antenna TX0 and
the first-2 transmission antenna TX2 transmitting the code-divided
transmission signals are spaced apart by the second horizontal
distance 2A in the horizontal direction, the receiving antenna
receiving the reflection signal reflected from the object may have
the same effect as that the first code division receiving signal
and the second code division receiving signal which have the same
shape are shifted spatially in the horizontal direction by 2A.
[0123] At this case, receiving antenna which is virtually present
due to the horizontal separation of transmission antennas may be
expressed as "a virtual receiving antenna" in a concept
distinguishable from actual receiving antennas.
[0124] Assuming that the first-1 transmission antenna TX0 in FIG.
4B is a reference, the first receiving antenna RX0, the second
receiving antenna RX1, the third receiving antenna RX2 and the
fourth receiving antenna RX3 may be real receiving antennas.
[0125] Meanwhile, since the first-1 transmission antenna TX0 and
the first-2 transmission antenna TX2 transmitting the code-divided
transmission signals are disposed in the same vertical position as
the receiving antennas in the vertical direction, so that all the
real receiving antennas and the virtual receiving antennas are
disposed at the same vertical position.
[0126] In addition, as described above, since the second receiving
antenna RX1 and the third receiving antenna RX2 may be synthesized
as one signal in the receiving mode, they may be represented by one
channel.
[0127] As a result, as shown in FIG. 4B, three real receiving
antennas including a first real receiving antenna RRX0, a second
real receiving antenna RRX1 and a third real receiving antenna RRX2
may be formed in the receiving part.
[0128] At this case, the second real receiving antennas antenna
RRX2 arranged in the middle corresponds to a composite antenna of
the second receiving antenna RX1 and the third receiving antenna
RX2.
[0129] Meanwhile, the first-1 transmission antenna TX0 for
transmitting the transmission signal with the first code is used as
a reference and the first-2 transmission antenna TX2 for
simultaneously transmitting the transmission signal with the second
code is spaced by 2A in the horizontal direction, thereby the
receiving antenna that receives the signal transmitted from the
first-2 transmission antenna TX2 may have the same effect as that
the position thereof may be shifted by 2A in the horizontal
direction than the actual position. In this case, the receiving
antenna formed at the shifted position may be expressed as a
virtual receiving antenna VRX.
[0130] The real receiving antennas that receive the transmission
signals of the first-1 transmission antenna TX0 may be represented
as RX0, RX1, RX2 and RX3, and virtual receiving antennas that
receive the transmission signals of the second transmission antenna
TX1 may be represented as RX0', RX1', RX2' and RX3' is order to
distinguish them from the real receiving antennas. In addition, the
real receiving antennas may be indicated by a solid line and the
virtual receiving antennas may be indicated by a dotted line in
FIG. 4B.
[0131] Therefore, in FIG. 4B, three virtual receiving antennas
including the first virtual receiving antenna VRX0, the second
virtual receiving antenna VRX1 and the third virtual receiving
antenna VRX2 having the same arrangement as the real receiving
antennas may be formed at a position separated by 2A from the real
receiving antenna.
[0132] In this case, the first virtual receiving antenna VRX0 may
correspond to the virtual receiving antenna RX0' of the first
receiving antenna RX0, the third virtual receiving antenna VRX2 may
correspond to the virtual receiving antenna RX3' of the fourth
receiving antenna RX3, and the second virtual receiving antenna
VRX1 therebetween may correspond to the virtual receiving antenna
RX1'+RX2' or the second and third receiving antenna which are
synthesized into one signal.
[0133] As a result, three real receiving antennas RRX0, RRX1, and
RRX2 and three channels of virtual receiving antennas VRX0, VRX1
and VRX2 may be formed in the receiving part.
[0134] Meanwhile, since the first-1 transmission antenna TX0 and
the first-2 transmission antenna TX2 are spaced apart by the
horizontal distance 2A, the real receiving antennas and the
corresponding virtual receiving antennas are also spaced apart, by
a horizontal distance 2A.
[0135] Since the first receiving antenna RX0 and the fourth
receiving antenna RX3 are also horizontally spaced by the
horizontal distance 2A, the position of the first virtual receiving
antenna VRX0 may be exactly overlapped with the position of the
third real receiving antenna RRX2 (i.e., the fourth receiving
antenna RX3).
[0136] Therefore, as shown in FIG. 4B, first real receiving antenna
RX0 or RRX0, a second real receiving antenna RRX1 or a composite
antenna of RX1 RX2, third real receiving antenna RRX2 or RX3 and a
first virtual receiving antenna VRX0 or RX0' overlapped therewith a
second virtual receiving antenna VRX1 or a composite antenna of
RX1'+RX2', and a third virtual receiving antenna VRX2 or RX3' may
be sequentially arranged with a horizontal distance A from the left
side in the receiving part.
[0137] As a result, the entire aperture of the receiving antenna
set, i.e., the horizontal distance between the first real receiving
antenna RRX0 disposed at one end and the third virtual receiving
antenna VRX2 disposed at the other end may be 4A.
[0138] Therefore, according to the radar apparatus of the present
embodiment, the entire aperture of the receiving antenna may be
extended to 4A, thereby improving the resolution of the horizontal
direction information in the long range detection mode.
[0139] In general, since a radar apparatus performs an object
detection function that detects the distance to an object and the
speed and azimuth of the object using reception signals received
through a plurality of receiving antennas, in which in order to
increase precision of detection of an object (that is, increase
resolution), it is preferable that the radar apparatus has an
antenna system with an "expanded aperture structure" by increasing
the gaps between the receiving antennas.
[0140] The distance from an end to the other end of a receiving
antenna is the aperture and it is a very important factor of the
performance of a radar apparatus to provide an expanded aperture
performance by increasing the aperture of the receiving
antenna.
[0141] By providing an antenna system with an expanded aperture
structure, the position where a grating lobe is generated at the
receiving end is moved closer to the center position where the main
beam is positioned.
[0142] Accordingly, an "expanded aperture structure" or a "virtual
antenna system" is provided for the radar apparatus according to an
embodiment of the present disclosure in order to move the position
where a grating lobe is generated away from the center position
where the main beam is positioned, that is, to suppress grating
lobe.
[0143] In order to have the virtual antenna system, as shown in
FIG. 2, the radar apparatus 100 according to an embodiment of the
present disclosure may further include a virtual RX antenna creator
140 for creating a plurality of virtual RX antennas.
[0144] The virtual RX antenna creator 140, as described above, can
perform signal processing for generating signals having a
predetermined phase difference that depends on the gap between
receiving antennas on the basis of a signals received by actual
receiving antennas.
[0145] That is, the virtual RX antenna creator 140 performs signal
process for generating a virtual signal (a signal having a phase
difference from the actually received signal) as if a signal has
been received through a virtual RX antenna that virtually exists at
a position where there is no actual receiving antenna.
[0146] The "creating a virtual RX antenna" herein may have the same
meaning as "a reception signal that has not been actually received
is generated". In this respect, the arrangement structure (gap,
number etc.) of virtual RX antennas may have the same meaning as
the structure (gap, number etc.) of reception signals that are not
actually received.
[0147] By the virtual RX antenna creator 140, an antenna system in
which not only a plurality of receiving antennas actually exist,
but a plurality of virtual RX antennas virtually exist at the
receiving end can be provided.
[0148] The antenna system including a plurality of virtual RX
antennas virtually existing at the receiving end may be expressed
as an "antenna system having a virtual aperture structure".
[0149] As described above, in order to obtain azimuth information
or horizontal information in the mid/long-range detection mode, the
transceiver 120 of the radar apparatus according to this
embodiment, in the mid/long-range detection mode, may
simultaneously transmit the code-divided signals through the
first-1 transmission antenna TX0 and the first-2 transmission
antenna TX2 which are spaced apart from each other by the
horizontal distance 2A, and may receive and analyze the signals
received from the first real receiving antenna, the second real
receiving antenna, the third real receiving antenna (or the first
virtual receiving antenna), the second virtual receiving antenna
and the third virtual receiving antenna which are sequentially
spaced apart by a horizontal distance A, thereby it is possible to
measure the horizontal information (azimuth angle, etc.) of the
target at a medium or longer distance with high resolution.
[0150] As a result, the radar apparatus according to the present
embodiment may provide the extended aperture performance and may be
capable of precisely measuring the horizontal information of the
medium or long distance object by using the antenna arrangement
structure or the antenna system as shown in FIG. 3 and the signal
transmission and receiving structure as shown in FIG. 4.
[0151] FIG. 5 shows a case of detecting elevation information or
vertical information using the radar apparatus according to the
present disclosure, in which a timing diagram of signals in a
second detection mode for detecting vertical information (FIG. 5A)
and an equivalent state diagram of transmitting and receiving
antennas in this case (FIG. 5B) are provided.
[0152] In the second detection mode for obtaining the vertical
information such as the elevation angle of the object, the radar
apparatus according to the present embodiment may transmit
code-divided transmission signals through one of the first-1
transmission antenna TX0 and the first-2 transmission antenna TX2
and the second transmission antenna TX1 which are spaced apart from
each other by the vertical distance B in the vertical direction,
and may receive reflection signals at all of the receiving
antennas
[0153] Hereinafter, an example in which the first-1 transmission
antenna TX0 and the second transmission antenna TX1 are used for
obtaining the vertical information of the object is described, but
the present embodiment is not limited thereto. Alternatively, the
first-2 transmit antenna TX2 and the second transmission antenna
TX1 may be used. Referring to FIG. 5A, in order to acquiring the
vertical information of the target, the transceiver 120 may be
operable to turn ON the first-1 transmission antenna TX0 and the
second transmission antenna TX1 which are spaced apart from each
other for a predetermined period of time in one detection period
(0.about.T) and may transmit one transmission signal having the
first code A and the other transmission signal having the second
code B at the same time respectively.
[0154] Meanwhile, each of the four receiving antennas RX0 to RX3
may receive the reflection signal during the same detection period
(0.about.T). The processor 130 may analyze the receiving signals
received from four receiving antennas and three channels (RX1 and
RX2 are combined and used as one channel) and may obtain the
vertical information (height, etc.) or the elevation information of
the object.
[0155] FIG. 5B is an equivalent state diagram of transmission and
receiving antenna for detecting vertical information. In FIG. 5B,
the position of a first-1 transmission antenna TX0 for transmitting
a transmission signal with the first code may be used a reference
position, and the horizontal position of the second transmission
antenna TX1 for transmitting the transmission signal with the
second code may be identically expressed as the horizontal position
of the first-1 transmission antenna in order to illustrate only the
vertical positional relationship.
[0156] According to the virtual antenna forming Principle described
with reference to FIG. 4B, the first-1 transmission antenna TX0 for
transmitting the transmission signal with the first code is used as
a reference and the second transmission antenna TX1 for
simultaneously transmitting the transmission signal with the second
code is spaced by A in the horizontal direction, thereby the
receiving antenna that receives the signal transmitted from the
second transmission antenna TX1 may have the same effect as that
the position thereof may be shifted by A in the horizontal
direction than the actual position. In this case, the receiving
antenna formed at the shifted position may be expressed as a
virtual receiving antenna VRX.
[0157] At this case, the second real receiving antenna RRX2
disposed in the middle may correspond to a composite antenna of the
second receiving antenna RX1 and the third receiving antenna
RX2.
[0158] The real receiving antennas that receive the transmission
signals of the first-1 transmission antenna TX0 may be represented
as RX0, RX1, RX2 and RX3, and virtual receiving antennas that
receive the transmission signals of the second transmission antenna
TX1 may be represented as RX0', RX1', RX2' and RX3' in order to
distinguish them from the real receiving antennas. In addition, the
real receiving antennas may be indicated by a solid line and the
virtual receiving antennas may be indicated by a dotted line in
FIG. 4B.
[0159] Therefore, in FIG. 5B, three virtual receiving antennas
including the first virtual receiving antenna VRX0, the second
virtual receiving antenna VRX1 and the third virtual receiving
antenna VRX2 having the same arrangement as the real receiving
antennas may be formed at a position separated by A from the real
receiving antenna.
[0160] In this case, the first virtual receiving antenna VRX0 may
correspond to the virtual receiving antenna RX0' of the first
receiving antenna RX0, the third virtual receiving antenna VRX2 may
correspond to the virtual receiving antenna RX3' of the fourth
receiving antenna RX3, and the second virtual receiving antenna
VRX1 therebetween may correspond to the virtual receiving antenna
RX1'+RX2' of the second and third receiving antenna which are
synthesized into one signal.
[0161] As a result, three real receiving antennas RRX0, RRX1, and
RRX2 and three channels of virtual receiving antennas VRX0, VRX1
and VRX2 may be formed in the receiving part.
[0162] Meanwhile, since the first-1 transmission antenna TX0 and
the second transmission antenna TX1 are spaced apart by the
horizontal distance A, the real receiving antennas and the
corresponding virtual receiving antennas are also spaced apart by a
horizontal distance A.
[0163] Since each of the first receiving antenna RX0 and the fourth
receiving antenna RX3 is horizontally spaced from the midpoint of
the second receiving antenna and the third receiving antenna by the
horizontal distance the forming position of the first virtual
receiving antenna VRX0 may be overlapped with the position of the
second real receiving antenna RRX1 (i.e., the composite antenna of
the second receiving antenna RX1 and the third receiving antenna
RX2) in the horizontal direction. Similarly, the forming position
of the second virtual receiving antenna VRX1 may be overlapped with
the position of the third real receiving antenna RRX2 (i.e., the
fourth receiving antenna RX3).
[0164] In addition, since the first-1 transmission antenna TX0 and
the second transmission antenna TX1 transmitting the code-divided
transmission signals are spaced apart from each other by the
vertical distance B in the vertical direction, the forming position
of the first virtual receiving antenna VRX0 may be spaced apart
from the position of the second real receiving antenna RRX1 (i.e.,
the composite antenna of the second receiving antenna RX1 and the
third receiving antenna RX2) by the vertical distance B in the
vertical direction. Similarly, the forming position of the second
virtual receiving antenna VRX1 may be spaced apart from the
position of the third real receiving antenna RRX2 (i.e., the fourth
receiving antenna RX3) by the vertical distance B in the vertical
direction).
[0165] That is, the first virtual receiving antenna VRX0 and the
second virtual receiving antenna VRX1 are horizontally overlapped
with and are vertically spaced apart from the the second real
receiving antenna RRX1 (i.e., the composite antenna of the second
receiving antenna RX1 and the third receiving antenna RX2) and the
third real receiving antenna RRX2 (i.e., the fourth receiving
antenna RX3) by the vertical distance B.
[0166] Therefore, a phase difference or amplitude difference may
occur between the receiving signals received by the respective
reception channels or between the transmission signals and the
corresponding receiving signals due to the vertical distance
separation.
[0167] As a result, the vertical information such as the height of
the object or the elevation angle may be acquired by comparing the
phase difference or amplitude difference of the signal for each
receiving channel.
[0168] In particular, the vertical information of the object may be
acquired by comparing the phase of the reception signal at the real
receiving antenna RRX1 (i.e., the composite antenna of the second
receiving antenna RX1 and the third receiving antenna RX2) to the
phase of the reception signal at the first virtual receiving
antenna VRX0 or RX0' which is vertically overlapped with but
vertically spaced apart from the real receiving antenna RRX1 by the
vertical distance B.
[0169] There is also a difference between the phase of the
receiving signal of the fourth receiving antenna RX3 and the phase
of the receiving signal of the second virtual receiving antenna
VRX1 or RX1'+RX2'), information may be obtained. Therefore, the
vertical information of the object may be acquired by using such a
phase difference.
[0170] That is, according to the height of the object, the
propagation paths (propagation distance) of signals received by two
receiving channels (for example, a second real receiving antenna
and a first virtual receiving antenna) spaced by a vertical
distance B in the vertical direction may be different from each
other, thereby the phase or the amplitude of the receiving signal
at each receiving channel may also be different from each
other.
[0171] Accordingly, in the processor 130 of the radar apparatus may
analyze the difference of the phase or the amplitude of the
receiving signal at each receiving channel and can acquire the
vertical information such as the height of the object.
[0172] The second detection mode for detecting the vertical
information may be used both for detecting a short distance object
and for detecting a long distance object.
[0173] Although not shown, according to the present embodiment, in
the third detection mode for detecting the short range object, the
transceiver 120 may transmit the transmission signal through any
one of the three transmission antennas and may receive the
reflection signal from all of the four receiving antennas RX0 to
RX3.
[0174] At this case, since the second receiving antenna RX1 and the
third receiving antenna. RX2 may be combined and used as one
receiving channel, one transmission channel and three receiving
channels may also be used in the short range detection mode.
[0175] Alternatively, in the short range detection mode, the
transceiver 120 may transmit the code-divided transmission signals
through two transmission antennas and may receive reflection signal
using four receiving antennas as shown in FIG. 4 or 5. However, in
this case, only one of the code-divided transmission signals may be
used in order to detect the object.
[0176] That is, in the short range detection mode, the transmission
signal may be transmitted using only one of the three transmission
antennas, or may alternatively be implemented as the manner in
which code-divided transmission signals are transmitted by two
transmission antennas but only one transmission signal is used for
acquiring position information.
[0177] As described above, in the first detection mode for
detecting the long distance object, the first-1 transmission
antenna TX0 and the first-2 transmission antenna TX2 which are
spaced apart from each other by 2A in the horizontal direction may
be used so that the main lobe can increase while the side lobes can
be minimized thereby to enable detection of medium and long
distance objects.
[0178] On the other hand, in the second detection mode for
detecting the vertical information of the object, the first-1
transmission antenna TX0 (or the first-2 transmission antenna TX2)
and the second transmission antenna TX1 which are spaced apart from
each other by 2A in the horizontal direction and spaced apart from
each other by B in the vertical direction may be used.
[0179] When the transmission beam pattern in the second detection
mode is compared with the beam pattern in the first detection mode,
the size of the side lobe may be relatively large, and as a result,
the short distance object can be detected.
[0180] That is, the second detection mode may be used not only for
obtaining the vertical information of the medium-long range object
but also for obtaining the horizontal information and the vertical
information of the short distance object.
[0181] The vertical information and the horizontal information of
the object may be obtained with high precision in both the long
range detection mode and the short range detection mode by using
the manner described above with reference to FIGS. 4 and 5.
[0182] Therefore, according to the radar apparatus of the present
embodiment, since the vertical information and horizontal
information of the long range and the short range can be precisely
measured without any physical change of the radar device or an
additional device, the utility as the radar sensor for the vehicle
may be maximized.
[0183] The radar apparatus 100 or the transceiver 120 and the
processor 130 and the virtual RX antenna creator 140 included in
the radar apparatus may be may be implemented as a radar control
device that performs an object identification function by a radar
or as a module of an ECU
[0184] The radar control device or the ECU may include a processor,
a storage such as and a memory and a computer program capable of
performing a specific function. The transceiver 120, the processor
130, and the virtual RE antenna creator 140 may be implemented as
software modules capable of performing their respective
functions.
[0185] The radar apparatus 100 according to the present embodiment
may be implemented as a computer system connected to the antenna
system. The computer system may include one or more element of a
processors, a memory, a storage, a user interface input and a user
interface output, which are capable of communicating with one
another via a communication bus.
[0186] In addition, the computer system may also include a network
interface for connecting to a network.
[0187] The processor may be a CPU or a semiconductor device that
executes processing instructions stored in memory and/or in the
storage.
[0188] Memory and storage may include various types of
volatile/non-volatile storage media. For example, the memory may
include ROM and RAM.
[0189] In the radar apparatus having such a hardware configuration,
a software or a program for performing the functions of the
transceiver 120, the processor 130, and the virtual RX antenna
creator 140 may be stored or installed in the memory or the storage
unit, and may be executed by the processor.
[0190] More particularly, the computer system for performing the
controlling of the radar apparatus 100 according to the present
embodiment may execute software stored a memory so as to transmit
the transmission signal through the transmission antenna set and
acquire the object information based on the reception signal
received through the receiving antenna set as above.
[0191] In addition, the radar apparatus according to the present
embodiment may utilize a MIMO antenna system in order to achieve a
high detection accuracy or resolution in vertical and horizontal
directions.
[0192] More specifically, each transmission antenna may transmit a
signal having an independent waveform different from each other in
a MIMO system. That is, each transmission antenna transmits a
signal of an independent waveform differentiating from that for the
other transmission antennas, and each receiving antenna may
determine the transmission antenna transmitting the transmission
signal correspondent with the received signal reflected from the
target due to the different waveforms of these signals.
[0193] In addition, the radar apparatus according to the present
embodiment may be configured to include a radar housing for
accommodating a substrate and a circuit including the transmission
antenna and the receiving antenna, and a radome forming the
exterior of the radar housing.
[0194] The radome may be made of a material capable of reducing the
attenuation of the radar signal transmitted and received, and the
radome may be constituted as a part of an outer surface of the
vehicle component such as the front bumper, the rear bumper, the
grill of the vehicle and the side body of the vehicle.
[0195] The radome of the radar apparatus according to the present
embodiment may be disposed inside a vehicle grill, a bumper, a
vehicle body, and may be disposed as a part of the outer surface of
a part of the vehicle body, as a result, it is possible to provide
a convenience in mounting the radar sensor to the vehicle while
improving the appearance of the vehicle.
[0196] A radar apparatus or a radar system according to the present
embodiment may include at least one of a front detection radar
sensor mounted on the front of the vehicle, a rear detection radar
sensor mounted on the rear of the vehicle, and a side detection
radar sensor mounted on respective side of the vehicle.
[0197] The radar apparatus or radar system according to the present
embodiment may include an electronic control unit (ECU) or a
processor for analyzing the transmission and reception signals and
processing the data and thereby for acquiring information of the
target. In addition, a communication link including an appropriate
vehicle network bus such as a CAN may be utilized for the data
transmission or signal communication between the radar sensor
device and the ECU.
[0198] In this disclosure, the horizontal information may be used
with the same meaning as the azimuth information or azimuth angle,
and the vertical information may be used with the same meaning as
the elevation information or the elevation angle.
[0199] An example of a method of obtaining elevation/azimuth
information of an object, using the radar apparatus 100 according
to an embodiment of the present disclosure is described
hereafter.
[0200] FIG. 6 a flowchart illustrating a signal processing method
provided by the radar apparatus according to an embodiment of the
present disclosure.
[0201] FIG. 6 is a flowchart showing signal processing after
signals are received by the signal transmission/reception method
described above with reference to FIGS. 4 and 5.
[0202] The reception data obtained in step S610 may be
data-buffered in a unit sample size being processable in one cycle
(S620), and then frequency conversion (S630) is performed
[0203] Thereafter, the method performs CFAR (Constant False Alarm
Rate) calculation on the basis of the frequency-changed reception
data (S640) and extract elevation/azimuth information, speed
information, and distance information of a target (S650). The
frequency change in step S630 may use Fourier transform such as FFT
(Fast Fourier Transform).
[0204] FIG. 7 shows differences in a signal waveform and a
frequency band in a mid/long range detection mode and a short,
range detection mode in a radar apparatus according to an
embodiment of the present disclosure.
[0205] As in FIGS. 4 and 5, using the radar apparatus according to
this embodiment makes it possible to precisely measure azimuth
information of an object in both a mid/long-range detection mode
and a short-range detection mode.
[0206] In addition to this configuration, the radar apparatus
according to this embodiment may improve sensing performance by
using frequency bands and signal waveforms that are different in
the mid/long-range detection mode and the short-range detection
mode, which is described in detail hereafter.
[0207] In general, radar apparatus may have a wide frequency band
for transmission signals, large output, and resolving power or
signal sensing performance that is improved as the number of
waveforms output in one sensing period is increased.
[0208] However, the available frequency bands of automotive radars
are limited to avoid interference with other vehicles or other
electronic waves in a mid/long-range detection mode. That is, the
automotive radars can use wide frequency band in a short-range
detection mode because there is a low possibility of interference
with other radar apparatuses, but available frequency bands are
limited in many cases in a mid/long-range detection mode to avoid
interference.
[0209] Accordingly, in the radar apparatus according to this
embodiment, a first transmission signal in the mid/long-range
detection mode shown in FIG. 4 uses a first frequency band and have
a first number signal waveforms (Chirp) that are relatively fewer
in one sensing period T, and as second transmission signal in the
short-range detection mode uses a second frequency band higher than
the first frequency band and have a second number of signal
waveforms larger than the first number in one sensing period.
[0210] Further, output of transmission signals can be larger in the
mid/long-range detection mode than the short-range detection
mode.
[0211] That is, as shown in FIG. 7, so-called slow chirp
transmission signals that are generated in the first frequency band
of about 76.about.77 GHz and have a large waveform width are used
in the mid/long-range detection mode.
[0212] On other hand, so-called fast chirp transmission signals
that are generated in the second frequency band of about
76.about.81 GHz higher than the first frequency band and have a
small width of waveform are used in the short-range detection
mode.
[0213] Accordingly, the first number N1 of waveforms (Chirp)
included in one sensing period or cycle in the mid/long-range
detection mode is smaller than the second number N1 of waveforms
included in the one sensing period in the short-range detection
mode.
[0214] Meanwhile, the first frequency band and the second frequency
band may overlap each other or may be completely different
frequency bands.
[0215] In general, the fast chirp type that outputs a plurality of
waveforms for one sensing cycle has high sensing performance
instead of an increase in data and particularly it can secure
desired resolution from low output.
[0216] Therefore, as in this embodiment, since slow chirp
transmission signals having large output and generated in a low
frequency band are used in the mid/long-range detection mode, it is
possible to avoid interference with other radar apparatuses etc.
and secure needed sensing performance.
[0217] Further, since fast chirp transmission signals in a wider
frequency band are used in the short-range detection mode, it is
possible to secure needed resolving power from even low output.
[0218] As described above, the radar apparatus of this embodiment
includes the antenna systems shown in FIG. 3, and in order to
obtain azimuth/elevation information of an object, uses the signal
transmission/reception methods shown in FIGS. 4 and 5 and makes
frequency bands and signal waveforms of transmission signals
different in a short-range detection mode and a mid/long-range
detection mode, thereby being able to avoid interference with other
radar apparatuses and measure azimuth/elevation information of an
object with high resolution at both a midilong distance and a short
distance.
[0219] According to the embodiments according to the present
disclosure described above, two first transmission antennas
disposed on both sides of the transmission antenna set may be
arranged apart from the second transmission antenna disposed
between two transmission antennas by a predetermined vertical
distance in a first direction perpendicular to the ground, and the
four receiving antennas may be disposed apart from each other by a
predetermined horizontal distance, so that the vertical information
and the horizontal information of the object can be easily obtained
in the long range detection mode and the short range detection
mode.
[0220] In addition, in the above-described antenna structure, the
transmission antennas for transmitting the transmission goals is
differently selected according to the detection mode, thereby the
vertical information and the horizontal information of the object
can be obtained in the long range detection mode and the short
range detection mode.
[0221] As a result, it is possible to achieve the performance of
precisely measuring elevation and azimuth information of as object
in both of a mid/long-range detection mode and a short-range
detection mode, which is required for automotive radars, without
physically changing the radar apparatus or adding other
apparatuses.
[0222] In addition, according the antenna apparatus and the radar
apparatus of the present disclosure, the shapes of the frequency
band and the signal waveform of the transmission signal may be
different from each other in the long range detection mode and the
short range detection mode, so that the measurement resolution of
the horizontal/vertical information of the object may be improved
is both long range detection mode and the short range detection
mode, and an interference with other radar devices may be
prevented.
[0223] Even though all components of embodiments of the present
disclosure were described as being combined in a single part or
being operated in cooperation with each other, the present
disclosure not limited thereto. That is, all the components may be
selectively combined one or more parts and operated if it is within
the object of the present disclosure. Further, all of the
components may be implemented by single independent hardware,
respectively, but some or all of the components may be selectively
combined and implemented by computer programs having a program
module that performs some or all of functions combined by one or
more pieces of hardware. Codes or code segments constituting the
computer programs may be easily inferred by those skilled in the
art. The computer programs are stored in computer-readable media
and read and executed by a computer, whereby embodiments of the
present disclosure can be achieved. A magnetic storing medium, an
optical recording medium, and a carrier wave medium may be included
in the recording media of computer programs.
[0224] Further, terms `include`, `constitute`, `have` etc. stated
herein means that corresponding components may be included, unless
specifically stated, so they should be construed as being able to
further include other components rather than excepting other
components. Unless defined otherwise, all the terms used in the
specification including technical and scientific terms have the
same meaning as those that are understood by those skilled in the
art. The terms generally used such as those defined in dictionaries
should be construed as being the dame as the meanings in the
context of the related art and should not be construed as being
ideal or excessively formal meanings, unless defined in the present
disclosure.
[0225] The above description is an example that explains the spirit
of the present disclosure and may be changed and modified in
various ways without departing from the basic features of the
present disclosure by those skilled in the art. Accordingly, the
embodiment described herein are provided not to limit, but to
explain the spirit of the present disclosure and the spirit and the
scope of the present disclosure are not limited by the embodiments.
The protective range of the present disclosure should be construed
on the basis of claims and all the technical spirits in the
equivalent range should be construed as being included in the scope
of the right of the present disclosure.
* * * * *